CentOS - Mar 2021 - SHR in top command is zero and major page fault is frequent

Recently, I found that many processes in our server experienced high frequency
of major page faults. The disk IO on this server is also very high. I also
noticed that when I execute "top" command, for some processes, the
value in SHR column became zero. when I restart these processes, the values of
SHR became non-zero again. What could be the reason for frequent major page
fault? Is there any connection between zero SHR and major page fault?